Applications Area

Possible ELANA locations

The ELANA technique involves a platinum ring. A 2.6 and a 2.8 mm ring are enclosed in the Elana Surgical Kit. Therefore, the smallest possible recipient artery has a diameter of approximately 2.5 mm. Smaller arteries than this size are more peripheral in the brain. They tolerate temporary occlusion time because of intracerebral and leptomeningeal collaterals (these are ‘natural’ bypasses already existing in the human brain). Therefore on these vessels a conventional anastomosis instead of an ELANA is possible.

This picture indicates the possible ELANA anastomosis locations in the brain. The ELANA site has to be free of arteriosclerotic plaques or any other vessel wall disease.

Currently, also other possible recipient places inside and outside the skull are under investigation.

Possible ELANA bypasses

With the ELANA technique, a whole new spectrum of possible bypasses opens up in vascular neurosurgery. Because of the different possible proximal locations it can facilitate a high flow in the original direction of the bloodflow.

Extra-Intracranial High-Flow Bypass

As a proximal, extracranial anastomosis site the external carotid artery (ECA) or the superficial temporal artery (STA) can be chosen. This is preformed in a conventional way because, except from a small group of patients with an occluded ICA and collateral ophthalmic flow, patients tolerate temporary occlusion time in these regions. The distal anastomosis can be made in any area suitable for ELANA.

Schematic overview of an extra-intracranial bypass from the ECA to the ICA (left and the STA to the ICA (right). The bypass conduit can be constructed behind or in front of the ear. Indications could be giant ICA aneurysm, an occluded ICA or skull base tumors(see ‘ indications’ under ). Recently a mean postoperative flow of 156 cc/min was reported through these kind of ELANA Ec-Ic bypasses.

Intra-Intracranial High-Flow Bypass

The ELANA can also be used for Ic-Ic bypass grafting for more peripheral pathology. Depending on recipient size, degree of arteriosclerosis and if the site is surgical reachable, a proximal and distal ELANA or only a proximal ELANA can be perormed. Examples are shown in figure 3

Left: Ic-Ic bypass from the ICA bifurcation (ELANA) to an M3 branch of the MCA (conventional). Note that if an M2 branch is reachable with a minimal diameter of 2.5 mm without arteriosclerosis, an ELANA would be preferable. Mean flow of 53 cc/min was recently reported through these ELANA bypasses. Middle: Ic-Ic bypass from the ICA bifurcation (ELANA) to a right A3 branch (Conventional). Right: Ic-Ic bypass with a proximal (ICA) and distal (P1 part of PCA) ELANA anatomosis.

Future

New areas of ELANA bypass grafting will be explored such as the external carotid artery for a subgroup of ischemic patients who do not tolerate temporary ECA occlusion or even territories in vascular or cardiac surgery.